Mechanical arrow nocks

ABSTRACT

An arrow nock having a telescoping impeller and housing with resilient means for enhancing the acceleration of launch. In various embodiments, effective together or independently, the housing and impeller are configured and coupled to: create arrow rotation during launch; grip the bowstring during notching and release it during launch; and generate tracking signals.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This application is a continuation of U.S. application Ser. No.12/287,445 filed on Oct. 8, 2008, which is incorporated by reference inits entirety. The present invention relates to archery arrow nocks, andmore particularly to arrow nocks designed to yield superior ballisticarrow performance and to facilitate arrow recovery.

Archers all wish to have maximum control over the flight of their arrow.They often find it desirable to customize their arrows depending uponthe targets involved or game hunted and they seek reliability in theirequipment and consistency in its performance.

Satisfactory arrow flight involves: consistency, accuracy, distance,speed of travel, drop, reaction to cross wind, reaction to environmentand target penetration.

It is well appreciated that arrow flight is affected by the structure ofthe arrow and by the structure and nature of the launching bow.Simplistically, this is reflected in the use of properly weighted,straight balanced arrows cleanly launched by a well-strung tautbowstring. Satisfactory flight is determined by the equipment, bothduring launch and after arrow release. There are many arrow and bowdesigns having the objectives of improving arrow ballistics, improvinglaunch, controlling flight, extending distance, and enhancing targetpenetration. There are also many structures adapted for inclusion orattachment to arrow shafts and bows to achieve these objectives, eitherindependently or in conjunction with structural modifications of thelaunching bow.

It is recognized that the flight of an arrow is stabilized by rotation.This is commonly imparted by fletching affixed to the arrow whichinduces rotation responsive to air movement during arrow trajectory.Alternatively, arrow rotation may be induced before or during arrowlaunch by providing torsional force on the arrow shaft. Thus, it isunderstood that the arrow flight may be determined during the controlexerted over the arrow by the bowstring upon initial engagement, duringbowstring release, during bowstring pressure before launch, and as thearrow commences flight when the bowstring begins relaxation.

As a practical matter, it is also important to recognize the economicbenefit of having arrows that can be used with a variety of bows.Obviously it is also desirable to be able to reuse spent arrows,something that can be facilitated by appropriate tracking means, damageresistant and/or easily repaired or replaced components.

2. Description of Related Art

The prior art is replete with flight stabilizers, arrow acceleratingdevices and special nocks for attachment to specially designed arrows.Many devices are disclosed for attachment to arrows to track flight anddetect their landing sites.

U.S. Pat. No. 4,900,037 to Miller suggests that increased arrowacceleration can be obtained by inserting a spring within telescopingsleeves at the rear of a hollow arrow shaft. During bowstring, draw,this spring is extended. Upon bowstring release, energy is stored bycompressing the spring. This energy is released by spring extension asthe arrow leaves the bow.

U.S. Pat. No. 5,971,875 to Hill discloses a notched spinner tube havingspiraled grooves on its outer surface to engage dimples on the inside ofan arrow shaft that has been deformed by a special tool. When the arrowis launched, the spinner tube is forced into the arrow shaft and thespiral grooves of the spinner tube act upon the dimples on the arrowshaft causing the arrow to rotate.

U.S. Pat. No. 6,478,700 to Hartman discloses an arrow spin drive havinga screw shaft containing cam surfaces that cooperate with a guide insidea hollow arrow shaft to impart rotation when the arrow is launched.

U.S. Pat. No. 6,203,457 to Snook discloses a removable nock having aspecial curves notch into which the bowstring is placed. The notch has atwisted opening so that as the arrow leaves the bowstring, a torsionalforce is imparted.

U.S. Pat. No. 6,877,500 to Hollers and Edwards discloses a helicallyslotted spin tube attached to a bow for imparting arrow rotation as thearrow traverses the tube during launch. A nock drive assembly cooperateswith the bow spin tube. When the bowstring is released, the nock driveassembly moves laterally within the spin tube while a nock pin travelsalong the helical slot imparting rotation to the arrow.

Among other patents disclosing arrangements for inducing arrow rotation,on my note U.S. Pat. No. 4,111,424 to Schreiber et al, U.S. Pat. No.5,846,147 to Basik, and U.S. Pat. No. 6,595,880 to Becker. Of additionalpossible interest with respect to nocks designed to effect arrowperformance, one may note U.S. Pat. No. 4,900,037 to Miller, U.S. Pat.No. 5,134,552 to Call and Denen, and U.S. Pat. No. 5,186,470 to Eastonand Filice.

While the prior art contains disclosures of diverse archery equipmentcalculated to improve arrow performance, none of this disclosedequipment shows or suggests the structure of the arrow nocks embodyingthe present invention, or results attainable through the use of thesenocks. Nor is there any disclosure of arrow nocks containing elementsassembled in the manner of the present invention which can be applied toconventional arrows in the field to accommodate perceived fieldconditions.

SUMMARY OF THE INVENTION

Improvement of arrow ballistics requires attention to the structure andbalance of the arrow. This can in most cases be assured by use of knownconventional arrows and not impairing the proven characteristics ofthese arrows with weight and balance distorting supplementary devices.

The present invention is embodied in arrow nocks for attachment toconventional arrow shafts. These nocks improve arrow ballistics andincrease arrow velocity. They enhance the notching procedure, facilitatearrow tracking and permit discretionary selection of desired propertiesin the field.

The main object of the present invention is to economically providearrow nocks that can be installed on conventional arrows to improve theflight characteristics of the arrows when launched even fromconventional bows.

Another object of the invention is to provide an arrow nock suitable forinstallation on conventional arrows to enhance flight stability,acceleration, distance and target penetration.

Another object of the invention is to provide arrow nocks that can beselected and/or adjusted in the field, without special tools, to adaptconventional arrows for diverse conditions of target, environment andwindage.

Another object of the invention is to provide arrow nocks thatfacilitate safely securing arrows to the bowstring so that the bow maybe carried with the arrow mounted and ready to launch.

And, another object of the invention is to provide arrow nocks thatgenerate signals permitting an archer to track their arrows in flightand/or locate their arrows when spent.

The invention features a unique nock structure permitting filedinstallation on conventional arrow shafts.

In one embodiment, the featured arrow nock includes integral resilientmeans for generating arrow acceleration and velocity greater than thatimparted by the bowstring.

In a particular illustrative embodiment, the featured arrow unique nockcomprises housing and impeller elements that, upon release of alaunching bowstring, produce axial rotation of the arrow.

In another particular illustrative embodiment, the featured arrow nockcomprises a gripper that secures the arrow to a bowstring untilautomatically released during launch.

In another particular illustrative embodiment, the featured arrow nockincludes a signal generator that is activated when the arrow is launchedto generate a tracking signal that can be enabled during flight or whenthe arrow lands.

These objects and features are achieved with arrow nocks comprising acylindrical housing configured for rigid mounting at the end of aconventional arrow shaft. An impeller is axially mounted within thehousing and projects from one end thereof; the opposite end of eitherthe housing or the impeller terminates in a notch for engagement with abowstring. The housing and impeller are biased apart along their commonlongitudinal axis by resilient means. Cocking means are provided toovercome the bias and hold the housing and impeller in close proximity.When launched, from a bowstring, the nock is uncocked and under thepressure of the resilient means, the housing and impeller are driven inaxially opposite directions.

In one of several illustrative embodiments the nock housing and impellerare coupled to effect relative rotation about their common longitudinalaxis when axially displaced by pressure of the resilient means.

In another one of the illustrative embodiments, the nock is providedwith a movable gripper in the notch. This gripper is coupled to theimpeller to block the entrance to the notch when the nock is cocked andto automatically open the entrance to the notch when the housing andimpeller are driven apart.

In still another illustrative embodiment, signaling means and an energysource are provided. Electrical contact means are provided between thehousing and impeller to connect the signaling means and energy sourcewhen the nock is released during arrow launch. Depending upon thesignaling means and intent of the archer, a visual or audible signalwill be generated, either upon launch or at some predetermined timethereafter.

The details of the invention, and the manner in which the objects areachieved by the features of the invention, will be more fully understoodand appreciated from the detailed description and claims, taken inconjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an arrow incorporating an illustrativeembodiment of the invention;

FIG. 2 is a perspective view of an arrow nock embodying the features ofthe invention;

FIG. 3 is an exploded perspective view, partially in cross-section, ofan arrow nock showing the general configuration and orientation ofvarious principle components of an illustrative embodiment of theinvention;

FIG. 4 is an illustrative cross-section taken along the lines 4-4 ofFIG. 2;

FIG. 5 is an illustrative partial cross-section of a nock having acylindrical housing and impeller designed to rotate an arrow uponlaunch;

FIG. 6 is a cross-section view taken along the lines 6-6 in FIG. 5;

FIG. 7 is a cross-section view taken along the lines 7-7 in FIG. 5;

FIG. 8 is a schematic layout of the interior surface of a cylindricalnock housing showing one means for achieving the relative rotation,cocking and release of the housing and impeller.

FIG. 9 is a schematic layout of the exterior surface of a nock impellershowing one means for interaction with the inner housing surface of FIG.8 for achieving the relative rotation, cocking and release of thehousing and impeller;

FIGS. IOA through IOD schematically illustrate the relative position ofa bowstring and arrow during notching and launch;

FIG. 11 is a side view of FIG. 2 showing an arrow nock incorporating anillustrative embodiment of the invention which provides gripping meansfor securing an arrow to a bowstring before launch and releasing thearrow from a bowstring during launch;

FIGS. 12A and 12B are cross-sections taken along the lines 12-12 of FIG.11, showing bowstring release and bowstring grip positions,respectively; and

FIG. 13 is an illustrative partial cross-section taken along the lines4-4 of FIG. 2, showing a nock, according to the invention, that providesvisual arrow tracking.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

It is to be understood that the description and drawings are forillustrative explanatory purposes only. The embodiments have been chosento explain the principles, features and characteristics of theinvention, thereby enabling those skilled in the art to best utilize theinvention. All equivalent variations developed by those skilled in theart are contemplated to be part of the invention, limited only by thescope of the claims.

This description of preferred embodiments presents several specificstructures to illustrate the flexibility, concepts, and functioning ofmeans by which the invention may be practiced. To render the operationand concepts of the invention more understandable, the illustrationshave been enlarged and simplified. No attempts should be made to comparethe dimensions of the various Figures.

Clearly, the weight, weight distribution, and symmetry about the axis ofthe arrow, is important. Accordingly, the materials and components ofthe nocks featuring the invention must be selected and configured withthis in mind. In typical embodiments adapted for use with conventionalarrow shafts of 0.25 inch diameter, the housing of the nock would be ofsubstantially similar diameter, providing a smooth and uninterruptedtransition from the end of the arrow shaft. In an extended quiescentcondition, the nock may be 3.50 inches long from tip to tip. Thoseskilled in the art will appreciate the appropriate sizes of thecomponents described and will recognize the common materials andelements to be used in the assembly of practical structures embodyingthe invention.

FIG. 1 illustrates a conventional arrow 10 having a shaft 11, with a tip12 on its forward end and a bowstring notch 14 on its distal end. Notinfrequently, as in the present invention, notch 14 may be formed aspart of a separate attached nock 13, which rigidly mounted at the distalend of arrow shaft 11. Fletching 15 is commonly used to improve thearrow flight characteristics. While not necessary for arrows using thenocks of the present invention, fletching on either the arrow or thenock, is an option that may be adopted.

The present invention relates to the structure of unique nocks that aresuitable for mounting by partial insertion into the distal end of ahollow arrow shaft 11. Nocks embodying the unique features of theinvention may also be configured to slip over the distal end of arrowshafts.

FIG. 2 shows an arrow nock 20, according to an embodiment of theinvention, comprising a cylindrical housing 30, a projecting rod 22extending from the closed leading end 23 of housing 30 and a shaft 24projecting from the distal end 25 of housing 30. Bowstring notch element26 is provided at the rear of nock 20. Notch element 26 may be anintegral part of shaft 24, or may be rigidly attached thereto.

In the embodiments to be described, projecting rod 22 is dimensioned tofit within the hollow end of an arrow shaft either permanently or besecure frictional fit. As previously noted, rather than employingprojecting rod 22, the forward end of the nock may be formed as acylinder that would embrace the end of an arrow shaft. The outsidediameter of housing 30 is preferably substantially the same as thediameter of the arrow shaft to which the nock is affixed. Similarly, theouter diameter of bowstring notch element 26 is preferably substantiallythe same as the diameter of the arrow shaft.

FIG. 3 is an exploded perspective view, partially in cross-section,showing the structure of elements comprising an illustrative embodimentof the invention wherein use of the nock imparts speed and rotation tothe arrow during launch. In this embodiment, shaft 24 is an integralpart of an impeller 40 that is controlled to move axially within housing30.

Nock housing 30 is a cylinder with a leading end 23 and a distal end 25.Distal end 25 has a depending edge 34 defining an aperture 35 permittingaxial passage of shaft 24 while preventing passage of cylindricalportion 41 of impeller 40, thus insuring entrapment of portion 41. Theinner surface 31 of housing 30 is provided with a series of radiallydisposed longitudinally twisting guide channels 33 terminating near thedistal end in a circumferential channel 32. The nature andinterrelationship of housing 30 and impeller 40 will be described morespecifically in connection with FIGS. 5-9.

Nock impeller 40 includes forward cylindrical portion 41 having outsidediameter slightly less than the diameter of inner surface 31 of housing30, such that it may be axially mounted for translation within housing30.

Channel followers 42 are radially disposed about the surface ofcylindrical portion 41 in positions coinciding with guide channels 33.The height of followers 42 is substantially equal to the depth of guidechannels 33 so that during translation of impeller 40 through housing30, followers 42 are committed to track within guide channels 33. Asdescribed hereinafter, suitable configuration of channels 33 determineswhether or not there can be relative axial movement between housing 30and impeller 40.

Channel 32, at the distal end of housing 30, extends around the entireinner circumference and opens at the front end into guide channels 33.Followers 42 are configured to reside within the groove of channel 32when impeller 40 and housing 30 are at a predetermined extended axialposition relative to one another. In this position housing 30 andimpeller 40 are completely decoupled and may rotate without effect uponone another.

Resilient means 50 are interposed between the leading face 43 ofimpeller40 and the inside of front face 23 of housing 30. Resilient means 50provides an axial separating force between housing 30 and impeller 40.In the expanded quiescent position, channel followers 42 on impellersurface 44, are axially located within channel 32 and accordinglyhousing 30 and impeller 40 are free for independent rotation. The forceof resilient means 50 may be modified for use of the nock with variousarrows and particular bowstring tension, to achieve specific flightconditions. One expedient for effecting increased or decreasedcompression of resilient means 50 is shown as a tension screw 96 in FIG.13.

In this embodiment, resilient means 50 comprises a [com pression]spring. Suitably stressed and/or compressed rubber or other material mayalso be employed.

While one preferred embodiment of the invention provides a nock thatcauses rotation and added acceleration during arrow launch, it may alsobe advantageous for an archer to opt simply for added acceleration with,or without, the signaling features to be described hereinafter.

An acceleration nock only, as shown in the embodiment of FIG. 4illustrates a housing 300 that does not include cam grooves 33 andimpeller 400 does not have cam followers. The cross-section schematic ofFIG. 4, taken along lines 4-4 of FIG. 2, illustrates how a spring 500biases housing 300 and impeller 400 axially apart. It will be understoodthat translation of impeller 400 within housing 300 is effected byapplying external axial force in opposition to the force of biasingspring 500. This external force may be applied manually by the archerprior to or during notching the arrow on a bowstring.

Prior to arrow launch, nock housing 300 and impeller 400 are axiallypressed together by a compressing spring 500. During release from adrawn bowstring, housing 300 and impeller 400 are released and axiallydisplaced by the expansion of spring 500 whereby the arrow is subjectedto both the forward directed force of the bowstring and the forwarddirected force of the compressed spring, enhancing the driving force forits flight.

The FIGS. 5-13 show how nock of the present invention may be designed tocock accelerate, rotate, secure and track conventional arrows.

FIGS. 5-9 describe a design for coupling a housing 30 and an impeller 40to cock the elements and thereafter effect rotation.

FIG. 5 is an enlarged cross-sectional view of housing 30 with resilientmeans 50 removed and with impeller 40 positioned within circumferentialchannel 32. Four impeller followers 42 are distributed about the face ofimpeller cylinder 41, axially positioned in circumferential channel 32of housing 30. Rotationally, followers 42 are located for entrance intolongitudinal guide channels 33 when impeller 40 and housing 30 are movedtogether. The FIG. 6 cross-section taken along the lines 6-6 of FIG. 5reveals the circumferential freedom of impeller 40 within channel 32.The FIG. 7 cross-section shows the empty channels 33 when impeller 40 isat the distal end of housing cylinder 30.

Clearly, the axial position of impeller 40 within channels 33,determines the relative rotational position of housing 30 and impeller40. As impeller 40 traverses the portion of housing 30 containinglongitudinal channels 33, if impeller 40 is restrained from rotation,housing 30 will rotate, and with it, any attached arrow.

The specific configuration of channels 33 as at the discretion of thedesigner. To provide a nock simply for enhanced arrow acceleration andvelocity, channels 33 may be aligned with the axis of cylinder 30. Toprovide a nock for rotating an attached arrow during launch, channels 33may be twisted as they extend longitudinally along the length ofcylinder 30.

If channels 33 are to participate in the function of cocking the nock,as described hereinafter, they may be configured to include a cockingsection. Ifchannels 33 are to participate in activating a signal unit,they may be selectively configured at appropriate axial positions toeffect connection of a power source to the signal unit. The inventioncontemplates that specific nock design will be chosen to effect one ormore of the functions noted.

The number of guide channels 33 is not a limited factor. In theillustrative embodiment shown in FIGS. 5-9, there are four guidechannels 33, each with twisting or wrapping about 90 degrees of cylindersurface. This particular design provides interaction between channels 33and followers 42 to cock the nock, impart arrow rotation upon launch,and enhance arrow acceleration and velocity.

FIG. 8 is a layout view of the inner surface 31 of housing cylinder 30showing an illustrative configuration of channels 32 and 33 upon andwithin the inner surface 31 of cylindrical housing 30. As previouslynoted, these channels have a width and depth to accommodate followers 42on impeller 40.

Channel 32 is located at the trailing edge of housing cylinder 30,adjacent to depending end 34 and extends without interruption about theentire inner circumference.

Four channels 33 are longitudinally disposed over a portion 36 of innersurface 31. Channels 33 are in front of channel 32, each having a centerline traversing 90 degrees of the inner circumference. Each channel 33has an elongated longitudinal section 37 terminating at its trailing endin channel 32. Each channel 33 has a cocking section 38 at the leadingend adapted to receive a follower 42 when resilient means 50 ismaximally compressed and housing cylinder 30 is slightly rotated withrespect to impeller 40.

FIG. 9 is a layout of the surface 41 of impeller cylinder 41 with fourfollowers 42 disposed at 90 degree intervals about its circumference. Toappreciate the interaction of housing cylinder 30 and impeller 40, FIG.8 and FIG. 9 arejuxtaposed.

When housing cylinder 30 and impeller 40 are assembled, their couplingpermits free unimpeded rotation of the elements when followers 42 are inchannel 32; imposes relative rotation of cylinder 30 and impeller 40 asfollowers 42 move along portion 36; and prevents axial displacement whenfollowers 42 are in cocking sections 38.

In use, the nock is “cocked” by pressing nock impeller 40 into nockhousing 30, e.g., towards the tip of an attached arrow. This isaccomplished by applying compressive pressure between nock impeller 40and nock housing 30 while rotating either the arrow or impeller 40. Thispressure causes impeller 40 to track followers 42 within channels 33.Upon reaching the forward end of channels 33, followers 42 come to restwithin cocking sections 38 holding impeller 40 and housing cylinder 30together in a cocked condition with resilient means 50 substantiallyfully compressed. When impeller 40 is moved slightly forward, as duringarrow launch, followers 42 are urged to move into channel portion 36,forcing cylinder 30 and impeller 40 apart under the expansion ofresilient means 50.

Having described the structure of a nock exhibiting the features of theinvention, it is worthwhile to consider its operation when attached toan arrow and launched from a bow. While the nock may be cocked bypressing it forward and rotating the arrow or nock until it is cocked.This cocking action may also be effected during notching of the arrowonto a bowstring, by pressing and turning the arrow with the notch inposition on the bowstring.

FIG. IOA thought FIG. IOD schematically illustrates an arrow 10 notchedto a bowstring 101 during four relevant stages oflaunch from a bow 100.The stages comprise: notching, FIG. IOA; bowstring draw, FIG. IOB; arrowrelease, FIG. IOC; and arrow launch, FIG. IOD. In each Figure, therelaxed or neutral undrawn position of bowstring 101 is denoted bydashed lines 102.

The nock may be cocked either before or during notching arrow 10 ontobowstring 101. Drawing arrow 10 back with bowstring 101, as illustratedin FIG. IOB, does not change the cocked relationship of housing cylinder30 and impeller 40.

Upon release of bowstring 101, arrow 10 accelerates under the forwardpressure of the bowstring. In addition, the pressure on impeller 40causes followers 42 to slip out of cocking section 38 and the expansionof compressed resilient means 50 supplements the forward pressure ofbowstring 101, thereby enhancing the acceleration. While impeller 40remains secured against rotation by bowstring 101, the pressure ofresilient means 50 forces followers 42 along channels 33, and housing 30with attached arrow 11 begins to rotate.

As illustrated in FIG. IOC, bowstring 101 soon passes through itsneutral position. It then begins to decelerate and arrow 10 begins toseparate and commence its flight. The absence of forward pressure frombowstring 101 and the expanding pressure of resilient means 50 positionsfollowers 42 in housing channel 32 so that arrow 10 continues rotationwith no impediment.

Thus, upon launch, as arrow 10 leaves bowstring 101, as illustrate dinFIG. IOD, the arrow has received primary drive from bowstring 101,supplemental nock drive from resilient means 50, and nock rotation fromtranslation ofimpeller 40 in housing 30.

To recapitulate the results achieved with the unique nock of thisinvention: using a conventional arrow and bow, the archer has launched arotating arrow with improved ballistic performance; with accelerationgreater than that of the bowstring; and with enhanced flight anddistance. By making it unnecessary to use fletching, the archer, in hisdiscretion, may also improve performance under flight influencing windand other environmental conditions.

Before describing how the basic features of the invention may be used togrip the bow string with a cocked nock, and how the housing relative toimpeller movement can be used to develop tracking signals, it should beunderstood that nocks containing the features if this invention may bereversed end-to-end, so that the impeller is affixed to the arrow andthe housing is provided with a notch at one end. It is believed thatthere is no need to describe this apparent modification further.

With an understanding of the structure and cooperative relationshipbetween the elements of this invention, it will be seen that arrow nocksembodying these features lend themselves to the highly desirableinclusion of gripper elements that hold the arrow on the bowstring untilit is released during arrow launch. Such a gripping action removes theneed for use of friction elements within the notch. FIG. 11 is a sideview of the general cross sections taken along the lines 12-12 of FIG.11, showing release and gripping positions of grippers 57, 58.

The structure and functioning of nock housing 30 and nock impeller 40have been previously described. The particular illustrative gripperembodiment of FIGS. 11, 12 provides interaction of housing 30 andimpeller to effect arrow acceleration and rotation, but this is notnecessary to the gripper function.

Opposing slots 55, 56 are provided in the walls of bowstring notch 14,90° displaced from the opening of notch 14. Individual gripper leafsprings 57, 58, are positioned within slots 55, 56 and are dimensionedto move freely into and out of notch 14. Leaf springs 57, 58 haveopposing leafs with gripping distal ends 59, 60 and forward control ends61, 62. As illustrated in FIG. 12A, leaf springs 57, 58 are resilientlybiased to a quiescent condition within slots 55, 56 so that unless “set”they leave notch 14 open.

Forward control ends 61, 62 are secured within slots 55, 56 andquiescently project above impeller shaft 24. Accordingly, when impeller40 is moved forward into housing 30, passage through aperture 35 at therear end of housing 30, depresses leaf springs 57, 58 and causes distalends 59, 60 to enter and block notch 14.

Thus, as shown in FIG. 12B, when the nock is cocked with impellerfollowers 42 resting within cocking sections 38, leaf springs 57, 58 areforced into notch 14 at a position behind bowstring 101, securing thenock to the bowstring. During launch, impeller 40 moves towards the rearof housing 30, leaf springs 57, 58 resume their quiescent position, andnotch 14 is opened to permit release of bowstring 101.

The spring coupled housing/impeller gripper nocks of the invention,permit archers to safely carry their bow with the arrow notched onto thebowstring. Furthermore, using these nocks makes it possible to use clearunimpeded notch channels for friction-free arrow launch.

The value of being able to track and retrieve arrows has been mentionedabove. The arrow nocks embodying the features of this invention alsolend themselves to reliably generating signals to track flight paths oridentifying landing sites. FIG. 13 illustrates the components of such anock.

FIG. 13 is a cross-sectional view taken along the lines 4-4 of FIG. 2.Cylindrical housing 30, impeller 40, and spring 50 have may the basicstructure described above. By way of electrical schematic example, thisembodiment of the invention includes an energy source 90 and a lightemitting diode (LED) 91 connected responsive to the telescopinginteraction of housing 30 and impeller 40. The specific structure ofbattery 90 has not been illustrated. It is obvious to those skilled inthe art that typical [disc] batteries of appropriate capacity can

be mounted in an aerodynamically balanced position in housing 30, or inother embodiments, in the arrow itself.

The switching control in this embodiment is effected at contacts, 94, 95via the conducting surface of housing 30. Conductor 92 connects LED 91to contact 95. Conductor 93 connects LED 91 to contact 94. When impeller40 is in the position shown, i.e. after arrow launch, conductor 92completes the connection of LED 91 to the negative terminal of thebattery 90, via contact 95 and housing 30. The connection to thepositive terminal of battery 90 is effected through conductor 93,contact [92] 94 , spring 50 and tension screw 96.Any suitable design,making use of the telescoping relationship of housing 30 and impeller 40is considered within the scope of the invention.

Of course, the described LED signal circuit will be closed upon arrowlaunch. A sound source may also be included within the nock, or may besubstituted for LED 91. Indeed, inasmuch as the important function ofthe nock is to act as a switch, the invention contemplates even theremote location of signal devices, for example within the adjacenthollow shaft of an arrow.

Through the addition of time delay components, in ways immediatelyrecognized by those skilled in the art, the signal source can beactivated at some timed interval following arrow launch. Such nocksmight be furnished transmitters or audible signal generators to assistin locating spent arrows.

The invention will be seen to comprise an arrow nock for mounting on theend of an arrow shaft, comprising a cylindrical housing with atelescoping impeller and resilient means biased to hold the housing andimpeller apart. Cocking means are provided to hold the resilient meanscompressed positioning the housing and impeller with minimum axialdisplacement. The nock is uncocked upon arrow launch, permitting theresilient means to expand and effect maximum axial displacement betweenthe housing and impeller. This creates arrow acceleration and velocitygreater than that furnished by the launching bow.

In one embodiment, the housing and impeller are coupled to rotate whenthe resilient means expands. In another embodiment, a gripper isprovided to hold the arrow to the bowstring when the nock is cocked. Instill another embodi- ment, a signal source is provided and activatedwhen the arrow is launched. Each embodiment, alone and in combinationprovides exceptional arrow flight and/or recovery characteristics thatare of value to the archer.

While the individual embodiments of the invention have been shown anddescribed, it is contemplated that these embodiments may be used aloneor in combination. Modifications of these embodiments will be apparentto those skilled in the art. It is intended that such modifications areincluded within the definition of the following claims.

The invention claimed is:
 1. An arrow nock for mounting on an end of anarrow shaft, comprising: a housing having a longitudinal axisand, thehousing having a set of first and second ends leading end and a distalend; an impeller disposed along the longitudinal axis having a first enddisposed within the housing and a second end disposed outside of andprojects from the housing, wherein the impeller and the housing aremoveable relative to each other; wherein movement of the housingrelative to the impeller occurs rotationally and freely about thelongitudinal axis; and, a retainer depending edge to capture at leastone of the ends of the impeller being a first or end and a second end ofthe impeller within the housing, the housing having a distal end withthe depending edge defining an aperture to entrap the impeller.
 2. Thearrow nock of claim 1, wherein movement of the housing relative to theimpeller occurs translationally along the longitudinal axis and furthercomprising a decoupling member that causes the axial rotation of thehousing to become and the impeller being decoupled from the axialrotation of the impeller and able to rotate independent from each other.3. The arrow nock of claim 1, further comprising a resilient membermeans positioned to resist movement between the housing and theimpeller.
 4. The arrow nock of claim 3, wherein movement and rotation ofthe housing relative to the impeller occurs translationally along thelongitudinal axis and rotationally about the longitudinal axis.
 5. Thearrow nock of claim 4, further comprising a rotator configured to causean axial rotation of a resilient means causing the impeller and thehousing relative to each other to rotate in opposite directions when thehousing and impeller are translationally moved relative to each otheralong the longitudinal axis.
 6. The arrow nock of claim 5, wherein therotator is further configured to cause the axial, rotation of theimpeller in a first direction and to cause the axial rotation of thehousing in a second and opposite direction both when the impeller ismoved in a first translational direction relative to the housing andwhen the impeller is moved in a second translational direction relativeto the housing and housing are coupled to effect relative rotation abouttheir common longitudinal axis.
 7. The arrow nock of claim 5, whereinthe rotator is further configured to cause the axial rotation of thehousing in a first direction and to cause the axial rotation of theimpeller in a second and opposite direction both when the impeller ismoved in a first translational direction relative to the housing andwhen the impeller is moved in a second translational direction relativeto the housing rotation of the impeller and the housing occurs when theimpeller and the housing are axially displaced.
 8. The arrow nock ofclaim 5, further comprising a decoupling member that causes the axialrotation of the housing to become decoupled from the axial rotation ofthe impeller the housing and the impeller being decoupled and able torotate.
 9. The arrow nock of claim 8, wherein the rotator is comprisedof one or more rotator channels the nock comprises a plurality of guidechannels in the interior of the housing with at least one guide channelin the interior of the housing that each engage a respective engaging atleast one of a set of one or more followers extending from the exteriorof the impeller follower.
 10. The arrow nock of claim 9, each of thewherein at least one or more rotator channels having guide channel has afirst leading end and a second trailing end and each of the one or morerotator channels at least one guide channel being configured to causethe housing and the impeller too axially rotate relative to one anotherin opposite directions as the followers travel from the first end to thesecond end of each of the respective rotator channels.
 11. The arrownock of claim 9, wherein the decoupling member comprises a decouplingthe nock further comprises a circumferential channel formed in theinterior of the housing, the decoupling circumferential channel beingconnected to each of the one or more rotator channels and beingconfigured to engage each of, the one or more followers at least one ofthe at least one guide channel.
 12. The arrow nock of claim 9, furthercomprising: a locking member cocking section to prevent movement of theimpeller relative to the housing; and, a release member to release thelocking member and thereby permit movement of the impellerthe nock beinguncocked and able to rotate relative to the housing.
 13. The arrow nockof claim 12, wherein the locking member cocking section holds theresilient member in a compressed state means, and wherein release of thelocking member cocking section permits movement of the resilient membermeans and the uncocking of the nock forces movement of the housingrelative to the impeller.
 14. The arrow nook of claim 13, wherein therelease member is operative to each of the rotator followers from eachof the respective locking channels into the respective rotator channelwhen the housing and the impeller are translationally displaced relativeto each other along the longitudinal axis by a predetermined distance.15. The arrow nock of claim 12 13, wherein the locking member comprisesa locking channel cocking section is connected to one end of each of therotator Channels at least one guide channel to engage the rotatorfollowers and prevent the rotator followers from entering each of therotator channels at least one guide channel.
 16. The arrow nock of claim3, further comprising: a locking member to prevent cocking sectionpreventing movement of the impeller relative to the housing; and, arelease member to release the locking member and thereby permittheuncocking of the cocking section permitting movement of the impellerrelative to the housing.
 17. The arrow nock of claim 16, wherein thelocking member holds the resilient member in a compressed state, andwherein release of the locking member permits movement of the resilientmember and forces movement of the housing relative to the impeller. 18.An arrow nock for mounting on an end of an arrow shaft, comprising: ahousing having a longitudinal axisand, the housing having a set of firstand second ends leading end and a distal end; an impeller disposed alongthe longitudinal axis having a, first end disposed within the housingand a second end disposed outside of projects from the housing, whereinthe impeller and the housing are moveable relative to each other; adistal end of the housing configured to capture at least one of the endsof the impeller being a first end of the impeller and a second end ofthe impeller within the housing, the housing having a distal enddefining an aperture to entrap the impeller; a resilient member meanspositioned to resist movement between the housing and the impeller; alocking member to hold cocking section preventing movement of theimpeller in a fixed position relative to the housing; and, a releasemember to release the locking member to permita release from a drawnbowstring which is engaged in the nock causing the release of thehousing and the impeller permitting movement of the impeller relative tothe housing.
 19. The arrow nock of claim 18, wherein the locking membercocking section holds the resilient member means in a fixed state, andwherein release of the locking member the uncocking of the nock releasesthe resilient member means from the fixed state.
 20. The arrow nock ofclaim 18, wherein the release member is operative in response tocompression of the resilient member while in the fixed state.
 21. Anarrow nock for mounting on an end of an arrow shaft, comprising: ahousing having longitudinal axis and having a set of first and secondends leading end and a distal end; an impeller disposed along thelongitudinal axis having first end disposed within the housing and asecond end disposed outside of the housing projects from the housing,wherein the impeller and the housing are moveable relative to eachother; a means bowstring notch for engagement by a bowstring; a retainerto capture at least one of the ends of the impeller being a first end ofthe impeller and a second end of the impeller within the housing, thehousing having a distal end defining an aperture to entrap the impeller;a releasable gripper movable within the nock to selectively retain holdthe arrow on the bowstring, limiting disengagement of the bowstringprior to launch, and release the bowstring when the housing and impellerare axially displaced, providing clear passage for the bowstring uponlaunch of the arrow.
 22. The arrow nock of claim 21, further comprisinga resilient member means positioned to resist movement between thehousing and the impeller; and, a locking member to prevent cockingsection preventing the movement of the impeller relative to the housingand to hold holding the resilient member means in a fixed position; and,a release member to release the locking member to permituncocking of thenock permitting movement of the impeller relative to the housing, and,wherein the releasable gripper is operable to retain the bowstring whenthe locking member holds the resilient member in a fixed position nockis cocked.
 23. The arrow nock of claim 21 further comprising a resilientmember positioned to resist movement between the housing and theimpeller.
 24. The arrow nock of claim 23 wherein the releasable gripperfunctions as a locking member to prevent movement of the impellerrelative to the housing.
 25. The arrow nock of claim 21 wherein theposition of the releasable gripper is determined by the position of thehousing relative to the impeller.
 26. The arrow nock of claim 21 furthercomprising; an energy source; an electrical component operative whenconnected to the energy source; and a connector conductor mounted on thenock and the releasable gripper to connect the energy source and theelectrical component when the releasable gripper impeller is in apredetermined position.
 27. An arrow nock for mounting on an end of anarrow shaft, comprising: a housing having a longitudinal axis and havingset of first and second ends a leading end and a distal end; an impellerdisposed alone along the longitudinal axis having first a leading enddisposed within the housing and a second end disposed outside of thehousing, projects from the housing wherein the impeller and the housingare moveable in axially opposite directions relative to each other; anenergy source; an electrical component operative when connected to, theenergy source; and, a connector conductor mounted on between the housingand the impeller with the housing having a conducting surface which isused to connect the energy source and the electrical component when thehousing is in a predetermined position relative to the impeller.
 28. Thearrow nock of claim 27, wherein the electrical component comprises, asignal generator.
 29. The arrow nock of claim 28, further comprising atimer operative to establish the connection after predetermined timeinterval following operation of the connector conductor.